Rock-drill.



PATENTED JULY 21, 1908. R. H. ANDERSON.

ROCK DRILL.

APPLICATION FILED DEC. 27, 1905.

BSHEETS-SHEET 1.

106x91 Emma m PATENTED JULY 21, 1908.

No. 893,596. I

R. H. ANDERSON.

ROCK DRILL.

APPLICATION FILED DEC. 21, 1905.

3 SHEETS-SHEET 2.

PATENTED JULY 21, 1908.

R. H. ANDERSON.

' ROCK DRILL.

APPLICATION FILED DEG.2'7.1905.

s SHEETSSHEET 3.

l llllllllllll l lllllll llllllll [MENTOR drill forging are both obviated.

' According to this invention the separable head is formed with any desired form of cut- ROBERT HUTCHISON ANDERSON, OF GERMISTON, TRANSVAAL.

ROCK-DRILL.

Specification of Letters Patent. I

Patented 'July 21, 1908.

Application filed December 27, 1905; Serial-No. 298,485.

To all whom it may concern:

Be it known that I, ROBERT HUToHIsoN ANDERSON, a citizen of the United States of America, surveyor, and resident at the May Consolidated Gold Mining Company, Limited, Germiston, District of the Witwatersrand, Colony of the Transvaal, have invented certain new and useful Im rovements in Rock- Drills, ofwhich the follbwing is a specification, reference being had therein to the accompanying drawings.

The object of the present invention is to provide a novel form of drill for boring rock percussively, having a separable head attached in a special manner to the shank. The head is such that it may conveniently be cast in steel or otherwise manufactured of hard material at a-low price, so that while 0 eratin during use more efiiciently than t e usua present drills, it may economically be thrown away when blunted or destroyed and replaced by a fresh one. Thus the expensive lowering and raising of large quantities of drills into and from a mine and the cost of maintaining a blacksmiths shop for ting edge and at the base is shaped to fit snugly upon the'correspondingly formed end of the shank by simple backward pressure. It has been the practice heretofore to secure the separable head to the shank by using a rgid metal rod, passing through the head, an method lies in the fact that t e constant shocks and strain to which the rod are subjected tend to crystallize the particles thereof 1n places, and thus weaken the rod'and make it necessary to replace the same at frequent intervals. To obviate this difficulty I pass rearwardly from the head-a pliant or flexible tension and securing member, preferably wire or chain, whichextends to a tightening and holding device, located upon the shank at a point so far back that it need not enter the bore hole during use of the drill. Upon a yielding member of this character, the shocks and jars incident to ercussive boring of rock have no perceptible etrimental effect.

-By way of example, the accompanying drawings illustrating an embodiment of the invention'are appended. .Therem FigureI is a side elevation, artly in section, of an improved drill, Fig. I a view at right angles shank. The disadvanta e of this forged patterns. Figs. IV and V is readily cast in steel and has its'parts advantageously disposed for break" ing the rock inwardly towards the centerof the hole. It comprises a leading central point or punch 13, a series of chisel edged wings;

to Fig. I with the bit or head removed, Fig. III an end view of Fig. II; Figs. IV and V are enlarged perspective views of the head or bit, as seen from above and below res ectively; Fig. VI shows the invention applied to a hand jumper Fig. VII is an end view'of Fig. vVI. Figs. VIII and X are side elevations of modified forms of drills constructed in accordance with my invention and Fig IX is a section on line 99 of Fig. VIII.

1 indicates the drill shank upon the outer end 2 of which the head or bit 3 is located. Their contiguous faces are preferably flat, the better to withstand the transmitted compressive stresses. 'Bosses 4 roject from the periphery of the underside o the head and fit into corresponding recesses 5 in the shankend, their purpose being to preclude lateral or-rotative movement of the head 'u on the headis attache a exible wire or chain 7, which, in fixing the head, is passed down. the axial hole 8 in the shank to a bolt 9 which s ans a recess 10 formed in the shank near to t e rear end thereof. The wire 7 is attached to the bolt 9, by passing its end through a hole 11 therein or otherwise, and is wound thereon by turning the bolt head with a spanner; a nut 12 u on the bolt locks the same when the wire is sufficiently tight to thorou hly secure the head.

t will thus be manifest that while the head is perfectly firm to resist compressive .stresses due to the impacts of the drill'and is also incapable of displacement by any ordinary force tending to draw it off the shank,"

the device by whlch it is secured-is almost entirely'without the bore hole and does not interfere with the free working'of the drill in the hole, or the passing of the crushed rock therefrom.- I

As before mentioned the novel construction ermits the economical, use of heads or bits liaving more complicated and efficient cutting elements than those of the present solid drills, which are restricted to easily Thus that illustrated by 14 which enlarge the hole made .by the I punch and a following series of teeth 15 which operate uponthe remaining rock-sur-.

face to furtherem'arge and clean out the hole to its ultimate size. Again the head shown in Figs. VI and VII includes a central punch 16 cutting or splitting edges 17 followed by reamers 18 curved both radiallyto smooth out the hole and backwardly at the extremities to avoid undue attrition at those points; the configuration being obviously incapable of production on a commercial basis by forging. Any or all of the cutting edges of either head described maybe serrated as indicated at 19 to prevent premature flattening.

The hand jumper shown in Figs. VI and VII embodies the hereinbefore described cutting head with its fixing means and in addition a modification of the invention having for its object the preservation of that end of the jumper which is struck by the hammer. In this instance a separable cap 20 is fitted over such end and secured similarly to the cutting head, "i. e. by a wire '21 passing down and secured to a bolt 22 arranged in the same recess 10 as the bolt 9. I

It will be clear that while adhering to the essential broad features of the invention numerous modifications of the specific constructions described are. perm sslble. Thus instead of the single wire or chain 7 passing down the axial hole 8, a plurality of such. wires or chains may be carried down corre sponding channels 8 formed externally of the shank as shown in Figs. VIII and IX, the fixing and tightening means beingmodified or not. Again, in the case 'ofa machine drill the axial hole 8 may be continued to the rear extremity of the shank and the wire replaced by a secured rod 7 which is secured by a nut 20 working upon it andbearing against the shank end as shown in Fig. X.

It will be noted that, in each'of the embodiments of my invention illustrated the,

tension means is adapted to permit of a slight angular (tilting) movement of the head relative to the shank upon impact of said head against the rock, particularly where one side only of the head bears the shock or strain of the impact. In the practical use of my drill first one outer chisel or cutting edge and then another is requiredto bear the entire, or, a disproportionately large share of the shock or strain of the impact of the head against the rock. This causes the .head to tilt or rock slightly on the shank owing to the enormous pressure exerted on one side of the head, which results in a slight compression of the metal at the lower end'of the shank rearward of said side of the head or a wearing or chipping off of the peripheral edge of the lower end of the shank which cannot be avoided even by the use of the hardest and toughest steel available.

In the use of my drill the tension means which I employ permits the cutting head to tilt or rock slightly on the shank upon impact against the rock by virtue, either of its being flexible throughout its length or by virtue of the way in which the tension means holds the head, as by a non-rigid engagement. I

I claim as my invention 1. In a rock drill, a shank, a separable cutting head adapted to be secured to the lower end thereof, and tension means ada ted to secure said head u on said shank, said tension means being ac apted to permit of a slight angular movement of said ,head relative to the said shank upon impact of the cutting head against the rock.

2. In a rock drill, a shank, a separable cutting head adapted to be secured to the lower end thereof, the contiguous faces of said shank end and head being substantially flat, and tension means to secure said head upon said shank, said tension means being a apted to permit of a slight angular movement of sa1d head'relative to the tension means u on impact of the cutting head against t e rock.

3. In a rock drill, a shank, a separable cutting head. ada ted to be secured to the lower end thereof the contiguous faces of said shank end and head being flat, one of said faces being provided with recesses, the other of said faces being provided with correspondingly shaped projections, .and tension means to secure sa1d head upon said shank, the tension means being adapted to permit of a slight angular movement of the ead relative to said tension means upon impact of the said head against the rock.

4. In a rock drill, a shank, a separable cutting head, and flexible tension means to secure said head to said shank, said tension means being adapted to permit of a slight cutting head, flexible tension means adapted to secure said head to one end of said shank, said tension means being adapted to ermit of a slight angular movement of sai head relative to the shank upon impact of said head against the rock, and means to apply tension to said tension means ,located at or near the outer end of said shank.

6. In a rock drill, a shank, a cutting head adapted to fit snugly against a correspondingly formed end of the shank, means to prevent lateral and rotational displacement of said head, and flexible tension means to secure said head to said shank by the application ofsimple backward pressure thereon,

said tension means being adapted topermit of a slight angular, movement of the head relative to the shank, upon impact of said faces being provided with recesses, the other of said faces being provided with correspondingly shaped projections and flexible tension means to secure said head upon said shank, said tension means being adapted to permit of a slight angular movement of the head relative to the shank upon impact of said head against the rock.

8. In a rock drill, the combination of a shank, a se arable head adapted to be held thereto, anc means for holdlng the head to the shank and regulating the intimacy .of

contact therebetween comprising a bolt passing through the shank and a wire extending from the head to the bolt, said Wire being secured to the head and bolt.

9. In a rock drill, the combination of a longitudinally perforated shank, a separable head ada ted to be held thereto, and means for ho ding the head to the shank and regulating the intimacy of contact therebetween com rising a bolt passing transversely throug extending from the head, throughthe perforationin the shank, to the bolt, said Wire being secured to the head and the bolt.

10. In a rock drill, the combination of a shank having a recess near its rear ortion, a separable head adapted to be hel to said shank, and means for holding the head to the shank and regulating the intimacy of contact therebetween comprising a bolt passing transversely through the shank and spanning the recess therein, and a wire exthe shank and a wire tending from the head to the bolt and being secured to the head and bolt.

11. In a rock drill, the combination of a longitudinally perforated shank having a recess near its rear ortion, a separable head adapted to be he (1 to said shank and means for holding the head to the shank and regulating the intimacy of contact therebetween, comprising a bolt passing through the shank and spanning the recess therein and a wire assing from the head, through the erforation in the shank, to the bolt, said wlre being secured to the head and the bolt.

12. In a rock drill, the combination of a shank provided with recesses 11 on its end, a separable head adapted to be I1eld to said shank, means for placement of sai head comprising bosses rojecting from said head and ada ted to t into the recesses in said shank, an means for holding the head to the shank and regulating the intimacy of contact therebetween comprising a bolt passing through the shank and a wire extending from said head to said lgolt and being secured to the head and the In testimony whereof I afl'ix my signature in presence of two witnesses.

ROBERT HUTOHISON ANDERSON- 'Witnesses:

HAROLD ERNEST KISOH,

JABEz WARREN DENNING.

reventing rotational dis- 

